Screening Five Qi-Tonifying Herbs on M2 Phenotype Macrophages.

Area of Science:

• Immunology
• Pharmacology
• Traditional Chinese Medicine

Background:

• Tumor-associated macrophages (TAMs) with an M2 phenotype are crucial in the tumor microenvironment (TME) and linked to poor cancer prognosis.
• Regulating TAM polarization presents a promising strategy for cancer immune therapy.

Purpose of the Study:

• To screen Qi-tonifying herbs from Traditional Chinese Medicine (TCM) for their ability to inhibit M2 macrophage polarization.
• To investigate the molecular mechanisms of promising candidates, particularly total flavonoids from Glycyrrhiza Radix et Rhizoma (TFRG).

Main Methods:

• Screening of extracts and ingredients from five Qi-tonifying herbs for inhibition of M2 polarization in murine macrophages (RAW264.7) induced by IL-4 and IL-13.
• Assessing the expression of M2 markers (Arginase-1, FIZZ1, YM1, CD206) and M1 marker (iNOS).
• Investigating the effects of TFRG on STAT6 phosphorylation and miR-155 expression.

Main Results:

• Total flavonoids from Glycyrrhiza Radix et Rhizoma (TFRG) and Ginseng Radix et Rhizoma significantly inhibited Arginase-1 (Arg-1) expression.
• TFRG suppressed M2 macrophage migration, reduced M2 marker expression, and increased M1 marker expression.
• TFRG decreased STAT6 phosphorylation and increased miR-155 expression, indicating a mechanism for regulating M1/M2 polarization.

Conclusions:

• Several Qi-tonifying herbs and their components show potential for inhibiting M2 macrophage polarization.
• TFRG is a promising candidate for cancer immune therapy, acting partly by inactivating the STAT6 pathway and modulating miR-155.
• This study provides natural products for immune regulation in the tumor microenvironment.